The ash content is an approximate measure of the mineral content and other inorganic matter in biomass.

The ash content is used in conjunction with other assays to determine the total composition of biomass samples.

1.1 This test method covers the determination of ash, expressed as the mass percent of residue remaining after dry oxidation (oxidation at 575 ± 25°C), of hard and soft woods, herbaceous materials (such as switchgrass and sericea), agricultural residues (such as corn stover, wheat straw, and bagasse), wastepaper (such as office waste, boxboard, and newsprint), acid and alkaline pretreated biomass, and the solid fraction of fermentation residues. All results are reported relative to the 105°C oven-dried mass of the sample. For particulate wood fuels, Test Method E 1534 should be used.

1.2 The values stated in SI units are to be regarded as the standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.